this.dummy_root = dummy_root;
this.dummy_root_content = dummy_root_content;
this.stm_nodes = stm_nodes;
this.empty_xpath = empty_xpath;
this.check_fails = check_fails;
evaluator = new XPathEvaluator();
evaluation_context = new EvaluationContext();
evaluation_context.setDefaultNamespace("");
evaluation_context.addNamespaces(namespaces);
evaluator.setEvaluationContext(evaluation_context);